Abstract
Author(s): Wei-Hsi Chen, Pei-Cheng Wang, Yu-ChiehHsiao,Yu Chang and Tsai-YuehLuo
The purity and impurities of protected-H3MN-16ET, a homemade precursor for the radiopharmaceutical 188Re-MN-16ET applicable to hepatoma treatment, was determined by monolithic C18 reversed-phase high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry(HPLC-QqQMS) for drug safety and efficacy assessment. The chromatographic purity amounted to 96.3%, exceeding the quality criteria, and three impurities were found in the material. The major impurity with an abundance of 2.15% was the transesterification byproduct of 2-mercapto ethanol. In addition, in order to assay stability and decomposed causes, protected-H3MN-16ET under acidic / basic hydrolysis, oxidation, thermal- and photo- induced stress conditions were investigated by analyzingthe forced degradation products through the same HPLC-tandem MS method. The radiochemical precursordid not withstandacidic / basic hydrolytic conditions and was easily transformed into carboxylic acid. It was also decomposed under UV and thermal exposures. However, it may resist oxidation, because it did not bear any oxygen-susceptible functional group. The sulfur-bonded protecting group CPh3 may be UV sensitive and the major cause to account for photo degradation. Heat could induce the chemical to fracture C-N bonding of the long alkyl side chain
